1. Field of the Invention
The present invention relates to a method of and an apparatus for driving air flow (wind) direction control louvers of an air conditioner such as cooler, heater, air conditioner having both the cooling function and the heating function, air air cleaning function and the like. In particular, the present invention relates to a method of and an apparatus for driving wind direction control louvers, capable of accurately controlling the wind direction in a desired direction by accurately driving a horizontally-extending control louver or a vertically-extending control louver adapted to control the wind direction of an air conditioner.
2. Description of the Prior Art
Generally, air conditioners include a heating device for heating a cold air present in a room and supplying the heated air into the room again, and a cooling device for cooling a warm room air and supplying the cooled air into the room again. There has been also known an air conditioner having both the heating function and the cooling function. Recently, these air conditioners also have had a cleaning function for cleaning a contaminated room air and supplying the cleaned air into the room again.
Referring to FIG. 1, there is illustrated an indoor unit of a conventional air conditioner having a cooling function, namely, a cooling device (generally called "aircon"). In FIG. 1, the indoor unit is denoted by the reference numeral 10. Of course, the air conditioner also includes an outdoor unit not shown. In FIG. 1, the reference numeral 12 denotes an air inlet for introducing an air present into a room into the interior of the indoor unit 10. The reference numeral 14 denotes an air outlet for supplying the air cooled by a heat exchanger equipped in the indoor unit 10 into the room again. The heat exchanger will be described hereinafter, in conjunction with FIG. 2. On the other hand, the reference numerals 16 and 18 denote a horizontally-extending control louver and at least one vertically-extending control louver for controlling the direction of the air supplied into the room through the air outlet 14, respectively. The horizontal control louver 16 controls the vertical wind direction whereas the vertical control louver 18 controls the lateral wind direction.
FIG. 2 is an elevational view in section of the cooling device. In FIG. 2, elements corresponding to those in FIG. 1 are denoted by the same reference numerals. In FIG. 2, the reference numeral 20 denotes the heat exchanger. When the room air introduced into the interior of the indoor unit 10 passes through the heat exchanger 20, it comes into contact with heat exchanging fins of the heat exchanger 20, which are kept at a low temperature by a cold refrigerant flowing in the interior of heat exchanger 20, and thereby achieves a heat exchange with the refrigerant.
The reference numeral 22 denotes a fan which discharges the air cooled by the heat exchange achieved in the heat exchanger 20, into the room through the outlet 14.
FIG. 3 is a block diagram illustrating a control system for a control louver driving device employed in the above-mentioned conventional air conditioner. In FIG. 3, the reference numeral 30 denotes a drive selection panel 30 which is typically constituted by a key matrix. The drive selection panel 30 is adapted to convert a user's control command into a corresponding signal to be outputted. The reference numeral 32 denotes a control unit which generates a drive signal, based on the user's control command received from the drive selection panel 30. The reference numeral 34 denotes a fan driving unit which receives an appropriate drive signal from the control unit 32 and drives the winding fan 22 shown in FIG. 2, based on the received drive signal. The reference numeral 36 denotes a control louver driving unit which receives an appropriate drive signal from the control unit 32 and drives the control louvers, based on the received drive signal.
Each of the appropriate drive signals is a pulse signal having a predetermined frequency. On the other hand, the control louvers include the horizontal control louver 16 and the vertical control louver 18.
The control louver driving unit 36 includes a motor (not shown) adapted to be actuated by an appropriate drive signal generated from the control unit 32 to drive the control louvers. The motor may be a step motor which is typically employed in conventional air conditioners.
The air conditioner including the control louver driving device having the above-mentioned construction initiates its operation when the user pushes down a selected drive button of the drive selection panel 30.
When the air conditioner initiates its operation, the control unit 32 sends an appropriate drive signal to the fan driving unit 34 which, in turn, drives the fan 22, based on the received drive signal. As the fan 22 is driven, air present in the room is introduced into the interior of indoor unit 10 through the air inlet 12 and then heat-exchanged with the heat exchanger 20, so that it may be cooled. The cooled air is then continuously discharged through the air outlet 14 by the winding fan 22 to be introduced into the room again.
The control unit 32 also sends an appropriate motor drive signal to the control louver driving unit 36. The motor drive signal is a pulse signal having a predetermined frequency for actuating the step motor of the control louver driving unit 36. The step motor of the control louver driving unit 36 is driven or rotated by the pulse signal outputted from the control unit 32. By the driving of the step motor, the horizontal control louver 16 and/or the vertical control louver 18 are driven.
At this time, the air discharged out of the air outlet 14 by the fan 22 is introduced into the room while being controlled in direction by the horizontal control louver 16 and/or the vertical control louver 18.
In the above-mentioned conventional construction, however, the signal, namely, the pulse signal sent from the control unit 32 to the control louver driving unit 36 has a constant frequency. As a result, an accurate wind direction control meeting the user's desire may not be achieved when the control louvers are inaccurately driven in cases where they are bent due to an external influence such as a variation in temperature or where a foreign matter such as dust is caught in a gap defined by a rotation portion of each control louver. In other words, where the control louvers are bent or where a foreign matter such as dust is caught in each control louver, the load is increased. However, the torque of the step motor is constant without being varied in accordance with the increased load. This is because the frequency of the drive pulse signal outputted from the control unit 32 is always constant. Consequently, the control louvers may be inaccurately driven.